The ability of a material to resist permanent indentation is known as hardness.
Brinell Hardness Test
During this test, an accurately controlled force is maintained when an indenter, generally a carbide ball, is forced into the test model for a specific period of time. Upon removal, it leaves an encircling indentation, the measurement of which is taken to calculate material hardness as per the formula.
Rockwell Hardness Test
For each individual test, a little load is forced to either a steel ball or diamond cone indenter located on the surface of the test material to set up a zero reference point. This is followed by applying the main load for a specific period of time, with the minor load applied on releasing. The hardness number is the variation in deepness between the shift due to major load and the zero reference position.
Vickers Hardness Test
With a maximum test load of 50 kg, the Vickers Hardness Test can be performed on both the macro and micro hardness scales. This sort of test is done by putting controlled force to an indenter over a period of time, which is a square-shaped diamond pyramid. The test load and impression measurement are employed with the required formula for calculating Vickers hardness value.